Looking to change the color underneath the skin
Use Bake, and then edit them outside blender (for example with Gimp).
The vertex paint can replaced using dynamic paint.
You can bake the vertex colors at the render panel. There, you will find the bake mode &quot;Vertex Colors&quot; which will export the vertex painting.
In your image editing software, you can change the hue or brightness or whatever and after image processing, you can bring it back as a texture.
As for applying the modified vertex paint to your model, the following QA will be helpful.
How to bake uv map texture to vertex color (selected to active)?